The present invention relates to an absorbent article, such as a sanitary napkin, a disposable diaper, an adult incontinence pad, and a panty liner. More particularly, it relates to an absorbent article which has excellent absorption performance and is extremely comfortable while worn, causing little stuffiness.
Absorbent articles which prevent an internal humidity rise and stuffiness while worn have been proposed. For example, Japanese Patent Laid-Open Nos. 6-218007 and 7-132126 disclose absorbent articles comprising an absorbent member containing oven-dried pulp, a large quantity of a superabsorbent polymer, and a hygroscopic material, such as silica gel or lithium chloride, and a breathable backsheet.
Japanese Patent Laid-Open No. 10-508521 (WO96/14037) discloses an absorbent article having a combination of two breathable sheets as a backsheet so as to prevent liquid from oozing out through the backsheet.
However, these related techniques leave a discharged body fluid as non-fixed among paper or pulp fibers so that a body fluid, if discharged in a large amount, generates water vapor to cause stuffiness.
Japanese Patent Laid-Open No. 7-184956 proposes a sanitary napkin which prevents back-flow of an absorbed liquid from an absorbent member by using an absorbent member having a specific retention of simulated blood after equilibrium absorption and swell followed by centrifugation and a specific rate of transmission for simulated blood. Japanese Patent Laid-Open No. 6-287886 discloses a multi-layer absorbent sheet comprising a surface layer (a layer with which a body fluid is brought into contact first) prepared from a mixed fiber containing bulky cellulose fiber by a papermaking technique and at least one base layer which is superposed on the surface layer. Japanese Patent Laid-Open No. 9-156013 proposes an absorbent sheet comprising a superabsorbent polymer and bulky cellulose fiber, the absorbent sheet having incorporated therein hydrophilic fine fiber or hydrophilic fine powder.
None of these related techniques makes a proposal on a structure which can markedly suppress water vapor generation thereby preventing stuffiness even when a large amount of a body fluid is discharged or should be absorbed.
An object of the present invention is to provide an absorbent article which hardly causes stuffiness and gives a comfort to a wearer even when a large amount of a body fluid is discharged and exhibits high absorptivity and excellent leakproofness.
Another object of the present invention is to provide an absorbent article which hardly causes stuffiness and gives a comfort to a wearer even when worn for a long time and exhibits high absorptivity and excellent leakproofness.
The present invention accomplishes the first object of the invention by providing, in its first aspect, an absorbent article comprising a liquid permeable topsheet, a liquid impermeable backsheet, and a liquid retentive absorbent layer, wherein the absorbent layer comprises a superabsorbent polymer and hydrophilic fiber or foam that does not swell with water or hydrophilic fiber or foam that has a water retention of 0.7 g/g or less when it is swollen with water and then dewatered by centrifugation, and the absorbent article has a physiological saline fixing ratio of 90% or more when it absorbs 10 g of physiological saline and, after 5 minutes, is dewatered by centrifugation.
The present invention also accomplishes the second object by providing, in its second aspect, an absorbent article comprising a liquid permeable topsheet, a liquid impermeable backsheet, and a liquid retentive absorbent layer, wherein the backsheet is breathable, and the absorbent article has a physiological saline fixing ratio of 90% or more when it absorbs 10 g of physiological saline and, after 5 minutes, is dewatered by centrifugation.